Add brandy, Tawny Port, and egg yolk to a cocktail shaker without ice and dry shake vigorously for 10 seconds to emulsify the egg yolk.
Add ice and shake again hard for a further 15 seconds until well chilled.
Double-strain into a chilled cocktail glass.
Garnish with freshly grated nutmeg over the surface.
The dry shake before adding ice is essential - it emulsifies the egg yolk fully, producing a noticeably smoother, creamier texture that a wet shake alone cannot achieve.
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